A metal rack would be more useful when it is provided with one or more drawers or slidable baskets in addition to the normally included horizontal shelves. In the early stage, rails are directly welded to the posts of the metal rack. As a result, the metal rack could not be disassembled to occupy a big room, and is not easily movable.
Currently, there are various types of sectional racks available in the market. Most of these sectional racks include vertical posts and horizontal shelves. Among others, there is a sectional rack using cone-shaped sleeves to connect the shelves to the vertical posts. When it is desired to mount a rail on the sectional rack, first weld two cone-shaped sleeves front and rear ends of the rail, and then connect each end of the rail to one post via a cone-shaped lining provided on the post. The gross weight of the rail and the drawer supported on the rail pulls the cone-shaped sleeves downward to tightly press against the cone-shaped lining, so that the rail is firmly fixed on the posts. However, when the drawer is pulled outward, there is a relatively large load on a front section of the rail and a relatively small load on a rear section of the rail, resulting in a lifted rear end of the rail and accordingly, a rail deviated from a desired horizontal position.
There is still another type of sectional rack having posts provided with insertion holes. Shelves or hangers may be fixed on the posts via hooks inserted into and located in the insertion holes. A rail for mounting on the rack is provided at an outer side with hooks, which are extended through the insertion holes and then moved downward to hook on the posts. However, since there is always a considerably large gap left between an upper end of the hooks on the rail and an upper edge of the insertion holes, the rail tends to move upward and downward relative to the posts, and is therefore not ideal for use.